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Effects of a hot, dry summer on forage quality

Alberta’s harsh winters can have serious effects on trees, shrubs
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Submitted by Alberta Agriculture

In many parts of the province, a hot dry summer has hastened the maturity and dormancy of native and improved pastures. This has reduced the quality and digestibility of the plant material as compared to a year with cooler temperatures and higher amounts of rainfall.

“Plants do not grow as tall as normal in dry conditions,” says Barry Yaremcio, beef/forage specialist, Alberta Ag-Info Centre. “Fibre levels increase faster and overall energy content of the forage is reduced. Fibre is the most difficult part of the plant for rumen microbes to breakdown. Feed remains in the rumen for longer periods of time. The longer the feed is resident in the rumen, the less an animal is able to eat, resulting in lower total daily nutrient intake.”

Hot dry conditions also limit the amount of water and nutrients available to the plant. “The amount of nitrogen absorbed by the roots and transferred into the plant is lower, resulting is lower protein production and less protein available in the leaf material. Protein is required to keep rumen microbial levels high to maintain proper digestion. A lack of protein in the plant material limits microbial growth in the rumen. A reduction in feed intake occurs and animals may drop body condition.”

Protein content in the forage drops more rapidly than normal in stressed plants. “Instead of pasture forage meeting protein requirements until mid-to late-September, it’s possible that protein requirements of the lactating cow will not be met by mid-August. As result, you can expect reduced milk production and lower calf growth rates.”

More mature forages can become very hard and brittle especially the wheatgrasses and fescues. “It may seem from a quick drive-by inspection that there’s sufficient forage for the animals to eat. If cattle ignore these plants and don’t want to eat them, you should consider this material as having no feeding value and it shouldn’t be considered as a potential feed supply. Take time, walk the pastures and determine what’s left behind. It’s possible to have cows in over mature unpalatable grass that’s up to their knees or bellies and they are unwilling or unable to eat enough to meet nutrient requirements.”

Overgrazing a pasture this fall can reduce winter survival of certain species. “Alfalfa and orchard grass are two prime examples,” says Yaremcio. “Plant counts next spring could be substantially lower pastures are grazed at the wrong time of year or too extensively. Overgrazing this fall may also delay plant development next spring which delays turnout, and could also reduce next year’s yield potential.”

For more information, call the Alberta Ag-Info Centre at 310-FARM (3276).

Trees, shrubs and winter

“As we enjoy the beauty of our trees and shrubs during the spring, summer and fall, we need to be mindful that Alberta’s harsh winter conditions can kill or deteriorate their vigor,” says Toso Bozic, agroforestry specialist, Alberta Agriculture and Forestry. “We can’t prevent winter from coming, but we can do a few things to prepare trees and shrubs to better survive it.”Choosing appropriate tree and shrub species is the first step, says Bozic, followed with proper tree planting and maintenance during the growing season.

“When winter does arrive, cold temperature, wind, winter sun, frost, heavy snow, or freezing rain can greatly damage needles, buds, branches, bark and even roots. Heavy snow and ice can break branches or topple down a whole tree. Winter wind will create evergreen needle desiccation. As winter creates shortages of food for wildlife, various rodents, deer and moose will feed on branches and bark, and greatly damage trees. Even birds feeding on too many tree buds can create damage.”

There are a number of things that can be done now to help prepare trees for winter.

Watering - “It’s crucial to water trees as soon as deciduous trees lose their leaves and before the ground freezes,” says Bozic. “Evergreens don’t go to full dormancy and may use the water in winter. Water will freeze around the roots and will be the only water available to survive a possibly dry spring.”

Some tips:

Water slowly and deep around the drip line (the outmost circumference of the tree canopy where water drips to the ground) and not close to the tree trunk. If you have younger trees, water at the root ball. One way to water is to make few small holes in 10 gallon bucket, fill it with water and stand it on the roots. You may also use drip irrigation or deep watering. Whatever method you use, don’t let water run off quickly.

Mulching - Having four to six inches of mulch helps keep moisture and prevent freezing of the roots. Don’t put much of the mulch next to the trunk; rather, create a donut shape of mulch around the tree.

Removing leaves and dead vegetation - Dead leaves and understory vegetation are home for many insects and diseases during winter. Raking and removing dead leaves will reduce the potential of diseases and insects coming back next spring.

Pruning - “Pruning is usually recommended during the winter and spring here in Alberta with the exception of 3D (dead, diseased and damaged) branches,” says Bozic. “Removing 3D branches will reduce the snow or ice weight on the whole tree and eliminate a potential host for many insects and diseases. You should also eliminate weak branch connections.”

Animals - Rodents, deer and moose can greatly damage or kill trees and shrubs. “Protecting your trees is a long-term and frequently costly battle,” says Bozic. “For example, you can use wire mesh products, tree plastic tubes, various repellants or electrical wires to deter deer and moose.”

Salt - Salt used for deicing is one of the major killers of trees and shrubs in Alberta as the run off damages roots, hinders growth and reduces foliage. The best solution is to eliminate use of salt, if possible, or plant trees and shrubs that can withstand salt damage.

“Every plant has its own mechanism to survive winter harshness,” adds Bozic. “I’m always amazed to see what our trees and shrubs survive here in Alberta. Making a few small changes can help them survive the winter and flourish again in spring as beautiful trees and shrubs.”